Starting system



Nov. 3, 1936; A. D. D owD 2,059,564

STARTING SYSTEM I Fi'ledjdarch s, 1934 INVENTOR I A.D.DOWD

4 ORNEV till Patented Nov, 3, 1936 OFFICE" s'r'rnm srsrnw Andrew D. Dowd, Montelair, N. 1., t

w gnor to Bell Telephone Laboratories, Incorporated, New

' York, N. Y.,

a corporation oi New York Application March 3,1934, Serial No. new s c. (or. lit-69.5)

This invention relates to an arrangement for controlling the movement of movable elements and more particularly to an arrangement for starting. in phase the movable elements of an velectro-optical picture reproducing system.

An object of the invention is to provide a starting arrangement for the movable elements at difierent stations, respectively, of a picture reproducing system which is novel, simple, and efiective in operation.

In. accordance with the embodiment of vention herein shown and describedrior the purpose of illustration, there is provided at the receiving station of a picture reproducing system a; circuit arrangement which may be conditioned for operation by momentarily closing asingle switch. After being thus conditioned the circuit is set to be operated by the interruption oi unmodulated carrier current received from the transmitting station and when, thus operated a clutch magnet is energized to connect the movable elements of the picture receiver to a driving motor. After the receiving circuit has been conditioned for operation the actual transmission of the picture is initia by momenty closing at the transmitting station a switch which simultaneously causes the interruption of the carrier current which is normally transmitted to the receiving station and the energization of a clutch magnet which connects the movable elements or" the picture transmitter to a driving motor. When the clutch magnet at the receiver is subcenuentiy deenergized, as for example aiter a complete picture has been transmitted, it cannot again be energized except by operating the circuitconditioning switch at the receiver and subeeoueutly' operating the so switch at the trans 11m False omration oi the clutch net is thus avoided.

The invention may be better understood by referring to the accompanying drawing in which l ly. 1 shows schematically the starting control circuit for the transmitter of a picture reproduc 537m; "in: and

' Fig. 2 shows schematically the starting control circuit for the receiver oi a picture reproducing system.

e invention is particularlyapplicable to pic t trion systems oi the type in which the drig motors for the movable elements at the two stations are continuously operated and magin which means are provided for disconnecting the movable elements of the system, the picture drums'ior example, from the motors. Systems of this type are disclosed for example in Patent. 1,606,227 granted to Joleph 'W. Horton et at,

the in November 9, 1926, and in a copending application of Frederick W. Reynolds Serial No. 713,939, filed March 3, 1934. -In systems or this type means are provided for operating the motors in synchronism and the variations corresponding to the tone values of the successively scanned elemental areas of the picture are transmitted in the form of a modulated carrier current.

Referring now to Fig. l of the drawing there is provided a clutch magnet "51 7111011, when operated, connects the movable elements of the picture transmitter to a driving motor. This clutch magnet is operated by the closure of contact M of switch l2; the circuit being completed from grounded battery it, through lamp it,contact Ill, winding of clutch magnet It;v auxiliary stop switch it to ground. The clutch magnet when operated is held up due to the co pletion of. circuit from grounded battery it is rough lamp i l, resistive momentarily operated aim causes the interrup-.

tion of the carrier current which is at the time being transmitted from the transmitting station to the receiving station. This is accomplished by completing the circuit from the sourceoi carrier current connected to the leads it and 2t through-the contact ill of the start switch and the contact it of the clutch magnet.- The contacts H and til of the start key it are so adjusted that the contact it closes before the contact it is closed. This is done to insure that the short circuit which is placed on the transmitted carrier current will be made at the instant that the clutch magnet is operated. The auxiliary stop it is provided to permit the attendant at the transmitting station to release the clutch at any time, thereby stopping the transmission of the picture.

There is also provided an adjustable contact it released, it being of the non-locking type, the

it and the adjustablestop contact short circuit which was placed across the source of carrier current is removed due to the opening of contact ii, and, due to the operation of the movable elements of the picture transmission apparatus by the driving motor, there is transmitted to the receiving station a modulated carrier current, the modulations being in accordance with the tone values of the successively scanned elemental areas of the picture. a

At the receiving station the circuit shown in Fig. 2 is conditioned by momentarily operating the start key 3| so that when the carrier current is interrupted at the transmitting station the clutch magnet Si is energized to connect the movable elements of the picture receiving apparatus to a driving motor. .The received carrier current after being rectified at the receiving station is impressed upon the circuit at 32. This circult is connected through the winding 88 of relay 34 to the light controlling apparatus of the picture receiver at 35.

when the start key 30 is momentarily operated the winding 0! relay 3! is energized by completing the circuit from grounded battery it through resistive element 38, through contact 39 of the clutchmagnet M, the contact of start key 3t, resistive element ,40, and the winding of relay it to ground. The operation of relay it removes a short circuit across the winding it of relay M by opening the contact ii. The relay it when opcr ated remains'energized alter the start lrey 3Q is opened due to the completion oi a circuit at contact 42 of relay 36. This energizing circuit may be traced from the battery Bl through resistive element/l8, contact 39 of the clutch magnet, reslstive element 43, contact 42, and the winding of relay 36 to ground. The winding M oi relay 55 is connectedto the contact 46 0! relay 36 through the contact 4'! of relay 36. Due to the opening 01' the contact ll of relay 38 the carrier current received over the line operates the relay 34 so that its armature rests against the contact at. A circuit is thus completed from grounded battery 81 through the contact 8 of relay 3t, contact ll of relay 36, and the winding ll of relay 4% to ground, thus operating the relay 4!. Aiter being operated the relay 45 remains energized due to the completion of the circuit from grounded battery 31 through resistive element 38, contact 88 of the clutch magnet, resistive element 48, contact I! of relay 5, and relay winding so to ground. The operation of relay 4! completes the circuit from ground through adjustable contact Bl, auxiliary stop switch", clutch magnet winding 3|, contac Uoirelaylitocontact "ctr-slay 3|.

Alter the receiving oircuithas been conditioned by momentarily operating the start key 30 as just described the transmitting operator is informed that the circuit is setup. for receiving a picture. The transmitting operator then operates the start key I! as before described to interrupt the transmitted carrier.

The interruption of the carrier causes the relay 34 to operate due to the bias current flowing tran grounded battery 31 through resistive element 55, winding It to ground. This causes the armature of the relay to close the contact at 56. For this condition the clutch magnet is energized by cur-" rent from grounded battery 3'! through the circuit including contact 54 of relay 34, contact 83 of relay 4!, winding of clutchmagnet 3|, auxiliary stop key 5!, adjustable contact I to ground. The

operation of the clutch magnet thus connects the I movable elements of the picture receiving apparatus to the driving motor. The energiz'stio'n' of the winding of the clutch magnet causes the'opening 0! the circuit at contact 3! and the closing or the circuit at contact 51. The clutch magnet thus remains energized by current from battery 81 through a circuit which may be traced from grounded battery through resistive element ll, contact 51, winding oi. clutch magnet 3 I, auxiliary stop switch 52, adjustable stop contact ii to ground. Due to the opening of the circuit at contact 39 of the clutch magnet, relays 36 and 45 are deenergized, that is, the circuit between battery 31 and the winding 50 and also the circuit between battery 31 and the winding oi relay 36 are opened. The deenergization of relay 3' closes the circuit at'contact'di and short circuits the winding 33 of relay 34. The short circuit across the winding 33 oi relay 34 prevents the introduction or a loss in the picture transmission circuit while the picture is being transmitted.

When the transmission 0! the picture is completed a contact 6i located on the base which supports the movable elements of the picture receivmg machine is automatically opened which releases the clutch and stops the rotation of the movable elements. This contact is adjustable is used to stop the machine at any time if required;

However, whenever the receiving machine is stopped it can only be started again by first momentarily operating the start key as to condition the starting circuit as above described and subsequently operating the start key I! at the transmitting'station to cause the transmission oi the carrier current to be interrupted.

In addition to the system disclosed in the Horton et al. patent and the Reynolds application referred to above there is disclosed in a copending application of Walter A. Phelps, SerialNo. 713,817, filed March 3, 1934, a systemoi the t to which this invention is applicable.

What is claimed is:

i. In a picture transmission system, means to produce unidirectional current from alternating carrier current, a clutch magnet toefiect the movement of a scanning device when energized, a first relay arranged to be energized by said unidirectional current, a second relay controlling the energization of said first relay, a third relay controlling the engrgization of said clutch ma!- net, a first clutch magnet contact closed when said clutch magnet is deenergized, a second clutch magnet contact closed when said clutch magnet is 55 energized, mearfito temporarily energize said second relay through said first clutch magnet contact to efiect energization of said first relay, a contact on said second relay closed when the relay is energized to energize said third relay through a contact on said first relay closed when said first relay is energized, a lockingwinding on said third relay energized through said first clutch magnet contact, a locking contact on said second relay clos- -ing.a circuit for said second relay also through said first clutch magnet contact, means to deenergize saidv first relay independently of said second relay to complete the energizing circuit for the clutch magnet under control 01' said third relay, and means to energize said clutch magnet over a circuit including said second clutch magnet contact. k

2. In a picture transmission system according to claiml in which the means to deenergize said first relay independentlr of said second relay 1 comprises a second clutch magnet, a flrst contact closed when said second clutch magnet is energized. means in series circuit with said first contact to complete a carrier interrupter circuit, and

means to energize said clutch magnet just subsequently to the operation of said series means.

3. In a picture transmission system having "a plurality of movable elementsone at each oi. a

. plurality of spacedv stations, independent driving a rotatable device, a biased relay having an armeans forsaid movable elements, and a clutch for connecting each movable element to its driving means, the combination of a circuit at one of said stations which may be conditioned to efiect the operation of the clutch at said station in response to anelectric signal received from a distant station, said circuit including means for preventvingthe operation of said clutch prior to theconditioning of said circuit, a single manually controlled switch for conditioning said circuit, means at said distant. station for energizing the clutch at said distant station and simultaneously causing the transmission of said electric signal, thereby simultaneously-starting the movement of said movable elements at the two stations, and means effective upon the operation of said clutch to automatically restore said circuit to its original condition. h

4. In a system for starting movable devices, a source of unidirectional current,- a clutch magnet which when energiied efiects the rotation of mature movable from a back contact to a front contact when the relay is energized by unidirectional current from said source, a second relay arranged to short circuit said source when deenergi'zed. a third relay having acontact for completing an energizing circuit for said clutch magnet when said biased relay is deenergized,

means to energize said third relay-over a circuit including the front contact of said biased relay and a contact of said second relay which is closed when the relay is energized, and means to temporarily energize said second relay whereby-said biased relay is also energized by current from said unidirectional source to condition the energizing circuit for said clutch magnet.

5. In a picture transmission system having an electrically operated clutch, a magnet for operating said clutch, a contact cooperating with said clutch magnet which is closed whensaid clutch magnet is not energized, means including said contact to eifect energization oi. the clutch magnet due to the interruption of carrier current,

and another contact cooperating with said clutch magnet closed by the energization of the clutch said means. 4

6. In a picture transmission system having a plurality of movable elements one at each of a plurality of spaced stations and a source of current, relay means to start the operation of one of said movable elements upon the interruption of the current from said source being supplied thereto, a second means to start the operation of the second of said movable elements, means to partially set up a circuit for interrupting the current from said source to said relay means and to complete shortly thereafter, a circuit for energizing said second means to start the movement of said second movable element, and circuit closing means operated in response to the operation of said second means to complete said interrupting circuit. a n

7. In a picture transmission system having a plurality of movable elements one at each of a plurality of spaced stations and a source of cur-' rent, means to start the movement of said first movable element uponvthe interruption of said current, a clutch magnet for starting the second of said movable elements, circuit closing means operated in response to the energization of said clutch magnet to partially set up a circuit for interrupting said current, a second circuit closing means in series circuit with said first circuit closingvmeans to complete the circuit for interrupting said current, and means to energize said clutch magnet subsequently to the operation of said second circuit closing means.

8. In a picture reproducing system having a plurality of movable elements one at each of a transmitting and a receiving station respectively, the'combination of clutch magnets at each of said stations which when energized effect the operation of said movabl e elements, means at the receiving stationfor preventing the energization of the receiving static clutch magnet, means under the control of t e receiving operator to condition said first mentioned means to permit clutch magnet when the first mentioned means has been. conditioned, and means responsive to the energization of the clutch magnet for restor-- ing said first-mentioned means to; its original condition.-

ANDREW .D. DOWD.

magnet to render its operation independent 0t 

